1. Field Of The Invention
The present invention relates to a colloidal metal dispersion, a colloidal metal complex and a process for the preparation of a colloidal metal complex. More particularly, the present invention is concerned with a colloidal metal dispersion in which colloidal particles of a metal are protected by a specific polymer, and with a colloidal metal complex comprising an amino group-containing compound and colloidal particles of a metal bound thereto through a specific protective polymer adsorbed on said colloidal particles. Further, the present invention is concerned with a process for the preparation of a colloidal metal complex. The colloidal particles of a metal in the colloidal metal dispersion of the present invention are readily bound to an amino group-containing compound to give a stable colloidal metal complex, which is not only useful as, e.g. a solid catalyst for various reactions, but also can be advantageously used for the study of living bodies and for the treatment and diagnosis of various diseases.
2. Discussion Of Related Art
It is well known that by the addition of gelatin to a colloidal gold dispersion, the dispersion becomes so stable due to the protective action of the gelatin that the colloidal gold can, for example, be dried without undergoing any change in color. Those which exert such protective action are called protective colloids. Besides gelatin, well known as protective colloids are natural high molecular weight compounds, such as albumin, gum arabic, protalbinic acid and lysalbinic acid. In addition, it has been reported that some synthetic polymers, for example, polyvinylpyrrolidone, polyvinyl ether and polymethyl vinyl ketone act as protective colloids and that when a metallic ion solution is subjected to reduction in the presence of these synthetic polymers, there is obtained a colloidal dispersion of fine particles of the metal protected by the polymers and the thus obtained colloidal metals can be used, for example, as catalysts (see e.g., "Industrialization of Polymer Catalysts" pp 151-179(1981)) publish by CMC Co., Ltd., Japan.
However, such known colloidal dispersions in which colloidal metals are protected by natural or synthetic polymers as mentioned above have problems. That is, colloidal dispersions in which the colloidal metal is protected by natural polymers, such as gelatin, have a drawback that they are instable and are not reproducible in respect of particle size distribution of colloidal metals. In the case of the colloidal dispersions in which colloidal metals are protected by the above-mentioned kinds of synthetic polymers, the reactivity of the synthetic polymers is low and, hence, it is difficult to strongly bind the colloidal metals to various substances. Therefore, the use of colloidal dispersions in which the above-mentioned synthetic polymers are used as protective polymers is limited, for example, to only the preparation of a catalyst for the hydrogenation of olefins.